Program for reading data off scanned graphs

Question

I know such thing exists, because I used it somewhat long ago ... the problem being I cannot remember what it's called.

I have some graphs from which I need to read off points (numeric values). The graphs are scanned, in one format or another, most of them being simple xy plots.

This program allowed to open the JPEG file, rotate it so it stands straight, click several clicks to establish the range of values (so it knows what some mouse movement stands for), and then when I click on the graph area, it would give me values of x and y variables.

It was incredibly useful when you have to read off some regression data shown off in way of graphs.

I know the explanation is a bit weird, but I gather anyone who knows of it, will understand. So, any ideas?

Answer 1

This one:

xyExtract Graph Digitizer 2.4

The "xyExtract" software is used for to extract data from a 2D graph (orthogonal and nonorthogonal axes) contained in a graphic file (scanned, PDF document or in a some file like GIF, JPEG, etc.).

The graphic file must be saved in a bitmap file. Then, the "xyExtract" converts the graph back to xy data file (up to 1500 points).

If you want, use the "Save Project" option on the "File" menu, for a posterior opening of the work. After each click, use the "Adjustment" option to move the marked point (pixel to pixel), if necessary.

Important: The xyExtract is a easy-to-use software and it guides you during whole the process for the points recovery.

Or this one:

DigitizeIt can automatically digitize scanned graphs and output data values.

DigitizeIt is an application that digitizes scanned graphs and charts.

Graphs can be loaded in nearly all common image formats (incl. GIF, TIFF, JPEG, BMP, PNG, PSD, PCX, XBM, XPM, TGA, and PCT) or pasted from the clipboard. Digitizing of line and scatter plots occurs automatically, and manual digitizing via mouse clicks is also possible.

Data values are transformed to a specified axes system and can be saved in ASCII format, ready to use in many other applications e.g. Microcal Origin or Excel. Axes can be linear, logarithmic or reciprocal scale.

Multiple different data sets can be defined and edited. It can handle tilted and distorted graphs, and includes comprehensive online help.

Or this one:

GetData Graph Digitizer lets you digitize graphs and plots

It is often necessary to obtain original (x,y) data from graphs, e.g. from scanned scientific plots, when data values are not available.

GetData Graph Digitizer allows to easily get the numbers in such cases.

With GetData Graph Digitizer, digitizing is a four step process:

• Open a graph
• Set the scale (coordinate system)
• Digitize (automatically or manually)
• Copy data to the clipboard, or export to TXT, XLS, XML, DXF or EPS file.

Or this one:

VKDigitizer

The program performs digitizing graphs (scanned images, etc.). For simplicity and reliability, it supports only manual point selection and rectangular coordinate system, but the image can be rotated to achieve precise alignment of axes.

The acquired data can be formatted according to the needs (number precision, column width, column separator, etc.).

Or this one:

jTechDig

jTechDig is a software tool written in Java for digitizing data from an image of graph or plot. jTechDig can import images from .gif, .bmp, .png, etc. files. After mapping of the coordinates system the data can be digitized manually by clicking the mouse.

The graphs can be magnified and panned for higher accuracy. The captured data can be saved to text file where the data are separated by semi-colon.

Or this one:

UnGraph

Often you see a graph, chart, picture or drawing and wish you could easily get hold of the X,Y data from which it was drawn. Now, you can scan such material with any scanner or photograph it with a digital camera and UnGraph will be able to give you the coordinates with a high degree of precision.

Or this one:

Didger

Didger is a highly accurate digitizing program that will be an invaluable addition to your software library. In seconds, Didger precisely transforms points, lines, or areas from your graphics, aerial photos, paper maps, imported vector files, scanned raster images or GeoTIFF photos to a versatile digital format you can use with your other software.

You name it and Didger can handle it quickly, accurately, and usefully. With Didger's multitude of features and ease-of-use, this is an unbelievable value, considering the time and effort you will save!! You will soon wonder how you have done your job without this indispensable tool.

Answer 2

I have developed a very easy-to-use web based program called WebPlotDigitizer to do exactly this. All you need is either Firefox 3.6+ or Chrome 6+ and point your browser here:

http://arohatgi.info/WebPlotDigitizer/

So all you have to do is drag and drop your plot in this and calibrate the axes by picking the four corners. Then just click along the curves and collect the data in .CSV format.

I would be open to suggestions regarding improvement of this tool.

Have fun!